it's useful to think about why we are taking these kinds of images--the background does not look attractive and there is no detail, lines or graphic interest in the plant at the angle in which its been taken.
Contrast needs to be more. Also, if you used flash it appears to have flattened the image too much. For shots like this it has more depth and separation of parts without flash, but that would mean longer exposure as well.
The green in this shot is bland... Less, or no, flash would have possibly created a more vibrant contrast between the two colors in the frame. Nice try. 4
3 - Not sure on your title, but matters not. This looks like a victim of too harsh flash. Composition seems quite good, unusual texture combinations, but not reached its full potential, in my opinion. A more refined crop, as mentioned the lighting and more 'interest' via textures or, angle, or something, make this better in my opinion. Tweaking of the colors slightly too, especially for this Chalenge.
The red is more brown than red, and the flash shadows are a bit harsh. Why this branch at this angle? It's not a really compelling subject. Good focus and sharpness, though, and I like the texture of the dirt (?) behind.